Electric heating unit



June 19, 1923.

c. A LAISE ET AL ELECTRIC HEATING UNIT Filed April 5 WWW? Nam! N ML N am u mJ m a WITNESS Patented June 19, 1923.

UNITED STATES PATENT OFFICE.

m! A. man, WIEEAWKEN, AND ALBERT I. GALIAGIB, 0! war omen,

NEW man.

ELECTRIC HEATING UNIT.

Application fled April 8, 1988. Serial Io. 550,579.

To all whom it may concern:

Be it known that we, CLnMnNs A. Lnsn and ALBERT J. Gamers, citizens ofthe United States, and residents, respectivel of Weehawken, HudsonCounty, State of ew Jerse and West Orange, county of Essex, and tate ofNew Jerse have jointly invented certain new an useful Improvements inElectric Heating Units, of which the following is a specification. 1

This invention relates to electric heating devices, particularly thoseadapted to be immersed in liquids and solutions for the pu se of heatingthe same.

eaters of this sort have a tendency to gradually deteriorate and burnout through oxidation of the resistance wire or element by theatmospheric oxygen enclosed in its protecting covering or casing incontact therewith at the high temperatures attained by these wires. Whenthis occurs, the heater may be restored by removing the heatin elementfrom its enclosing casing or shell an replacing it with a new element.As heretofore constructed the removal and replacement of the heating orresistance wire could not be accomplished without tools suited for thepurpose and the return of the heater to the factory and the services ofa mechanic were re uired.

An 0 ject of the present invention is to provide a heater of this'typein which the heating element is protected from oxidation.

Another object of the invention is to provide'a heater of the above typein which the heating element is rotected from oxidation by the provision0 an inert atmosphere in contact with the heating or resisting elethenecessity of using tools for this purpose.

A still further object of the invention is to provide a method ofprotecting heating elements from oxidation.

With these and. other objects the inven-" tion comprises the method andheater desizribed in the following specification and c aims.

Fig. 1 is a longitudinal sectional view of a heater embodying apreferred form of the invention. y.

Fig. 2 is a longitudinal sectional view of a heater embodying a modifiedform of the invention, an

Fig. 3 is a longitudinal sectional view of a form of heating orresistance element adapted to be used in the heaters shown in Figs. 2.

F g. 4 is a section on line 4-4 of Fig. 1. Fig. 5 1s a section on line5-5 of Fig. 2.

In the present invention the heatin or res stance element is containedin a she or casing which is filled with an inert or nonoxidlzing atmoshere. This atmosphere is formed by disp acing the air in the shell withnitrogen, carbon dioxide, hydrogen, ar-

on or a mixture of similar inert gases, or y enclosm in the casing orshell some eas- 11y oxidize substance such as finely divided metallicpowders, suboxide's or other reducmg substances capable of absorbing anduniting with the oxygen of the atmosphere and preventing it fromattacking the resistance element, or with some carbonate nitride orother material which decomposes at the temperatures to which the deviceis heated. Or .two or more of these methods ance core and wire areformed in a single unitary structure which may be inserted into orremoved from its enclosing shell or casmg as a unit. The element is soformed that it is held in position in the shell by means of a clampin orflanged collar or cap mounted on t e open end of the shell byscre'wthreads or other suitable means to permit the heating element tobe easily mounted or replaced.

Referring more particularly to the accompanying drawings, a resistancewire 10 is mounted on a core 12 of suitable heat resisting, insulatingmaterial having grooves 14 in which coils of the wire are mounted and isenclosed in a shell or casing 16 of fused silica or similar material.The shell 16 and the core 12 are so proportioned that the w1re 10 isvery close to or in contact with the wall of the shell to provide a veryeflective heat transfer from the wire the liquid in which the heater isimmersed.

One end of the wire passes from the lower end of the core upwardlythrough" a passage 18 to a terminal 20 mounted on a stopper 22 on whichthe core 12 is mounted and the other end of the wire passes over theouter face of the core to a terminal 24 on the stopper 22. The core,stopper and wire form a compact unitary structure which may be insertedinto and removed from the shell 14 as a unit. The stopper 22 is providedwith an outwardly extending flange 26 which is engaged and held betweenthe upper edge or mouth of the shell and a threaded cap 28 having aninwardly extending flange 30 engaging the flange 26 and holding thestopper in a rigid position in the shell and closing the interior of theshell from the atmosphere. The cap 28 is mounted on the shell by meansor a collar 32 of Ibakelite, condensite or similar non-corrosivematerial fitted on the shell 14 and provided with outward screw threadson which the cap may be readily screwed or unscrewed to permit the coreor the heating-cartridge to be readily removed without the necessity ofusing tools. A collar of insulating material 34 such a magnesia orasbestos is mounted on the upper part of the core 12.

lln assembling the heater the air within the shell is displaced with aninert or nonoxidizing gas such as nitrogen, argon or hydrogen or amixture of such gases and this gas mixture is retained in the shell whenthe heater is used and prevents or lessens the oxidation of theresistance wire.

An inert or non-oxidizing atmosphere may also be formed by coating thecoil or wire 10 with a readily oxidizable powder of metal or suboxideand in this case the air in the shell 14 need not be displacedas theoxygen will combine with the oxidi'zable powder and leave only nitrogenand other inert gases of: the atmosphere in contact with the resistancewire. An inert atmosphere may also be formed, as indicated'iu Fig. 3, byplacing a quantity of material 36, which gives an inert gas on heating,such as a readily decomposable carbonate or suitable nitrogen compoundin a cavity 38 in the core 12. As the heater becomes hot the materialgives oil nitrogen or carbon dioxide or other inert material to displacethe air and produces an inert atmosphere. This .method of formingthei'nert atmosphere is (ill very convenient and useful when a burnedout resistance wire is being replaced as it enables cores to be insertedwhich will generate an inert atmosphere and therefore may .be soldseparate from the casing for this purpose.

Instead oil a shell or casing of fused silica I other similarinaterialmay be used as illus.

trated in Fig; 2, the lining serving to .pro-

tect the metal part of the casing from con tact wlth the resistancewire. The metallic casmg may be made of aluminum, Tobin bronze, monel orother suitable metal which Through the above invention the life of theresistance wire is greatly lengthened and when the wire burns out or isotherwise in ured it may be easily and quickly replaced wlthout the useof special tools or skill.

. Having thus described our invention what we claim as new and desire tosecure by Letters Patent is:

1. A heater of the kind described having a casing of insulatingmaterial, a core having a resistance wire mounted thereon and positionedin said casing, said casing also provided with an inert atmospheretherein.

heater of the kind described which comprises a casing of insulatingmaterial, a core mounted in said casing and carrying a resistance wireand an inert gas developing means.

3. A heater oi the kind described which comprises a tubular casingclosed at one end and having a threaded open end, a cap adapted to screwonto said open end, a core having a portion adapted to be clamped tosaid tube by said cap and a resistance wire and terminals mounted onsaid core, and an inert atmosphere in said casing.

4:. A heater of the kind described which comprises a tubular casingclosed at one end and having a threaded open end, a cap adapted to screwonto said open end, a core having a. portion adapted to be clamped tosaid open. end of said tube by said cap a 63. A heating element forheaters of the kind described which comprises a core adapted to beinserted in a heater, a. resistance wire on sald core and a substance onsaid element for protecting said wire from,

oxidation when heated. v

7. A heatingelement'for heaters. of, the kind described which.comprisesla' core adapted to be inserted into a heater-,a resistancewire on said core and a substance in said element adapted to generateinert or non-oxidizing gases when heated.

8. In a device of the kind described5'a unitary structure consisting ofa supporting core provided with a stopper portion, a resistance Wire andterminals mounted thereon, the said core, wire and terminals beingadapted to be removably mounted as a unitary structure in a CilSlIlg.

9. A replaceable unit for heaters of the kind described, said unitcomprising a stopper adapted to fit a casing, terminal connectionssecured in said stopper, a core secured to said stopper, and a heatingelement supported on said core and connected in circuit to said terminalconnections.

10. A replaceable unit for heaters of the kind described, said unitcomprising a stopper adapted to fit a casing, terminal connectionssecured in said stopper, acore secured to said stopper provided with acavity therein, a filling in said cavity of inert gas developingmaterial, a heating element supported on said core and passing throughsaid cavity and connected in circuit with said terminal connections.

11. A replaceable unit for heaters of the kind described, said unitcomprising a stopper adapted to fit a casing, terminal connectionssecured in said stopper, a core secured to said stopper, said core beingprovided with a cavity therein, a heating element supported on said corepassing through said cavity and connected in circuit with said terminalconnections, said heating element carrying an inert gas developingmeans.

In witness whereof, we have hereunto set our hands at the borough ofManhattan, city, county and State of New York, this 7th day of April,1922.

CLEMENS A. LAISE. ALBERT J. GALLAGER.

